The Surgical Airway

1%

"In the National Emergency Airway Registry (NEAR II) study, less than 1% of more than 7,700 ED intubations involved cricothyrotomy." -Manual of Emergency Airway Management, 3rd Edition


To apply that statistic to prehospital care, assuming the average paramedic in the area performed 6 live intubations a year (the minimum required for certification), over a career of 30 years that paramedic will have performed 180 intubations throughout their career. According to these numbers, that paramedic will on average perform less than 1.8 cricothyrotomies. This skill is the epitome of low-frequency, high risk. 


Because of the low frequency of surgical airways, there is not much data to study. It has been said that the most difficult part of this procedure, is making the decision to do it. 


How are we, as providers, prepared for this truly once-in-a-career type call? Here are few of my thoughts on the matter. I'd love to hear yours.

Training

"This potential hesitancy is readily overcome by technical proficiency." -Manual of Emergency Airway Management, 3rd Edition

It is recommended that providers practice this skill one to two times each year using manikins or animal tracheas, or whatever is available. It has also been studied that those who practiced this procedure repeatedly in one session improved each time, performing the cricothyrotomy on a manikin in 40 seconds or less after their fifth attempt. 

Anticipate Difficult Airways

Early in my career, I had a patient with high velocity penetrating trauma to the left chest resulting in multiple wounds. I anticipated that this patient had a very high likelihood of deteriorating and in preparation for that, I was preparing for invasive airway management. Fortunately for me, a more seasoned colleague cautioned me- recognizing that this patient also had great potential to be a very difficult intubation. We determined the benefit of intubation in a more controlled environment, with more advanced equipment (and frankly more experienced providers) at a hospital 10 minutes away would outweigh the risks of allowing this patient to continue to self-ventilate and potentially worsen. We provided advanced notice to the hospital of our situation, and upon arrival to the ED, anesthesia was already there with all of their bells and whistles. After multiple attempts, the patient was finally intubated. My lesson learned from this call was to be better at anticipating a difficult airway, rather than rushing to intubate. 


I currently use gut-feeling to determine that level of difficulty, but there are some tools that may help make a more specific assessment and I am practicing being in the habit of using them to assess each patient I see (MOANS, LEMON, RODS, SHORT). 

The Decision

Having a solid airway algorithm helps in making the decision to move to the surgical airway. Studies have shown that for the typical laryngoscopist, if successful intubation hasn't been achieved in 3 attempts, it is unlikely that intubation will be successful. If a patient is unable to be intubated or oxygenated, the next step in the algorithm must be invoked. 

What do you use as your airway algorithm? 

In addition to the algorithm, there are rare instances where cricothyrotomy may be the primary means of airway management. These include foreign body in the proximal trachea, airway disruption or midface trauma such that intubation or extraglottic device wouldn't be expected to work, epiglottitis, angioedema, anaphylaxis, penetrating trauma to Zone 2 of the neck (jaw to clavicle). 

The Double Set

The prime example of the double set up is the patient who cannot be intubated after the 3rd attempt and cannot be oxygenated with the bag-mask. The double set involves one provider attempting to place an extraglottic device, while another prepares for cricothyrotomy. 

Percutaneous Transtracheal Jet Ventilation

Recently, my fire district has started carrying commercial kits for transtracheal jet ventilation (TTJV). So here's a little information I found that applied to this set up. The full details of these notes can be found in Chapter 16. 

TTJV is the surgical airway of choice for children younger than 10-12 years old, however it can be used for adults as well. In either case it is a temporary measure to buy time until a better airway can be placed. It is helpful to have a patent upper airway to allow for exhalation as obstruction may cause air stacking and result in barotrauma. A nasopharyngeal or oropharyngeal airway may assist in allowing for exhalation. 

The procedure begins with identifying landmarks and immobilizing the larynx. The syringe attached to the transtracheal catheter can be partially filled with fluid to watch for bubbles- lidocaine may be a good choice as it can be sprayed in the airway once placement is confirmed to numb the structures and suppress coughing. After advancing the catheter, placement should be confirmed again and jet ventilation performed. The catheter should be held in place by hand until a better airway is placed. 

Gas flow through a 14 gauge needle at 50 psi is 1,600 mL/second and elastic recoil accounts for exhalation. So for the average adult, an I:E ratio of 1:3 is recommended, or 1 second ventilation, 3 seconds exhalation. Pressure should be titrated down to the lowest pressure needed to deliver tidal volume (usually around 30 psi). Pressures for small adults and children should be less than 20-30 psi and for patients less than 5 years old, a bag should be connected (using an ETT adapter from a 3.0 ID ETT) to deliver ventilations at a lower pressure. 

In this temporizing measure, PaCO2 will increase by 2-4 mmHg/minute.

Complications include subcutaneous emphysema, barotrauma, catheter kinking, obstruction from blood or mucus, and esophageal puncture.